Abstract: A network latency estimation apparatus for estimating latency in a network communication between a server and a client. The apparatus includes an event observer to observe occurrences of pre-selected events occurring at the server. A logging device associated with the event observer logs into a data store the occurrence of the events together with corresponding time information. A latency estimator associated with the logging device uses the logged occurrences with the corresponding time information to arrive at an estimation of the latency for the communication.

Abstract: A network latency estimation apparatus for estimating latency in network communications between a server and a client. The apparatus comprises an event observer for observing occurrences of pre-selected events. The events associated with the communication occurring at the server. A logging device associated with the event observer for logging into a data store the occurrence of the events together with respective time information. A latency estimator associated with the logging device for using the logged occurrences with the respective time information to arrive at an estimation of a client's latency for the communication.

Abstract: A network latency estimation apparatus for estimating latency in network communications between a server and a client. The apparatus comprises an event observer for observing occurrences of pre-selected events. The events associated with the communication occurring at the server. A logging device associated with the event observer for logging into a data store the occurrence of the events together with respective time information. A latency estimator associated with the logging device for using the logged occurrences with the respective time information to arrive at an estimation of a client's latency for the communication.

Abstract: A network latency estimation apparatus for estimating latency in network communications between a server and a client. The apparatus comprises an event observer for observing occurrences of pre-selected events. The events associated with the communication occurring at the server. A logging device associated with the event observer for logging into a data store the occurrence of the events together with respective time information. A latency estimator associated with the logging device for using the logged occurrences with the respective time information to arrive at an estimation of a client's latency for the communication.

Abstract: A method and apparatus for detecting an error rate of a data stream. The data stream is divided into a sequence of blocks, and a detection interval is defined including a predetermined number of blocks in the sequence. For one or more of the blocks in the detection interval, respective error measures are computed responsive to the error rate of the data stream. The one or more blocks in the detection interval are classified as good or bad blocks by comparing the respective error measures to a first threshold. It is estimated that an error condition exists in the data stream by comparing a count of the bad blocks in the interval to a second threshold.

Abstract: A system and a method for a dynamic probability access protocol for determining access to shared channels. Some networks have a common channel which is shared by many users. A key issue in such networks is the allocation of the shared channel among many competing users. The system and method of the present invention enable media access control in shared bandwidth networks. When the user wishes to send a message, the user transmits with a probability p, which depends on the load on the channel. The probability p is announced by the network, and transmitted to the users as a broadcast message. Under conditions of low load, the probability p approaches 1, while at high load p is relatively low. This media access control protocol guarantees high channel utilization at high load, as well as low delay at low load periods. The proposed method is applicable on wireless networks, such as cellular networks and satellite-based networks.

Abstract: A method for tracking users of a cellular communications network in which the network pages users according to registration messages received from the users. Within each location area of the network, the cells are assigned identities. The cells broadcast codes representative of those identities to the users. In a first preferred embodiment, the identities facilitate the computation, by the users, of distance traveled. Each user transmits a registration message only after traveling a certain distance. In a second preferred embodiment, neighboring cells have different identities. Each user transmits a registration message only after exceeding a threshold number of transits from one cell to another. In a third preferred embodiment, each cell is assigned a unique identity. Each user transmits registration messages periodically, but only if the cell in which the user is located has changed since the last registration transmission.

Abstract: A method of allocating access to a shared media network, with specific application to tracking and paging mobile users of a cellular telephone network. Each cell of the network broadcasts a load factor .alpha., representative of the load on the cell's control channel. Each user in a cell determines a registration priority for itself, and also a registration threshold based on .alpha.. In the preferred embodiment of the present invention, each user is assigned a base threshold time T, and each user in a cell computes a registration threshold time T', based on T and .alpha., and registers its location with the network if the last such registration was longer ago than T'. Users are paged only in cells to which they could have traveled since their most recent location updates.

Abstract: A method is provided for providing a cache architecture for a database system having a given number of request streams and a given number of pages of random access memory available for use in one or more caches. The cache architecture includes (i) an allocation of memory pages over a number of caches, and (ii) an assignment of the request streams to the caches. Given that the number of caches is less than the number of streams, the method according to the invention allocates memory pages to the caches and assigns streams to the caches so as to optimize the memory access hit ratio for a given trace of memory requests from the streams. The method includes obtaining characterization information for the request streams (mean burst sizes and cache depth distributions based on the sequence of requests in the trace), and using the characterization information to predict the hit ratios for proposed superpositions of the request streams.